Generally, a sirocco fan is a curved multi-blade fan which blows air forward with a plurality of curved blades. The sirocco fan is quiet, and thus widely used in an air conditioner for home use or use in buildings or plant factories.
In the sirocco fan, the plurality of curved blades are arranged and installed in the form of a cylinder in a circumferential direction, and a fan thereof is connected to a motor shaft to be rotated, and thus a fluid is moved by a pressure thereof.
A volute duct for forming a path of the fluid is installed around the fan, and the duct is provided so that a cross section thereof is linearly increased along a circumference of the fan. Therefore, the fluid suctioned from upper and lower sides of the fan is transferred along the path of the duct, i.e. a volute to a discharge port, and then discharged.
The sirocco fan according to a related art generally includes one fan, a motor and a volute. Therefore, the fluid which is introduced perpendicularly to a rotating direction of the fan toward an opposite side to the motor is rotated like a tornado along the volute, which is gradually widened, by rotation of a vane, i.e., the curved blade, and then discharged to an outside.
In such a structure of the sirocco fan, since the path is formed in a volute shape, it is difficult to control a discharge direction thereof after the sirocco fan is fixed. When it is intended to change the discharge direction, the entire device should be rotated and then fixed again, and when it is intended to divide a discharge amount, various ducts may be used, but there is a problem that a great pressure loss occurs.
As a related technique which has been developed to solve the problem, U.S. Pat. No. 6,896,478 has been disclosed. Here, the sirocco fan is configured to have a multi-volute, but it is just configured so that a number of sirocco fans are structurally attached. However, a case in which the motor is used together may occur, but it is also a simple coupling structure.
Since the multi-volute sirocco fan according to the related art is just configured by structurally coupling the number of sirocco fans, there is problem that a cost is increased due to a multi-structure.